Raytheon Aircraft Company B36TC accident near Sugar Grove, Illinois, July 25, 2012
On July 25, 2012 at about 1:50 pm local time, a Raytheon Aircraft Company B36TC, registered N471BB, was substantially damaged in an accident during initial climb near Sugar Grove, Illinois (Aurora Municipal Airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The partial loss of engine power for reasons that could not be determined because postaccident testing and examination did not reveal any anomalies that would have precluded normal operation.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 25, 2012 · about 1:50 pm local time
- Place
- Sugar Grove, Illinois · Aurora Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Raytheon Aircraft Company B36TC
- Registration
- N471BB · no longer on the register · serial EA-694
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that shortly after takeoff, the airplane’s engine lost partial power and shook violently. The pilot elected to land the airplane in a cornfield off the end of the runway, where the it sustained substantial damage to both wings. A postaccident engine run performed with the engine still mounted on the airframe revealed no anomalies, but full-power testing could not be performed due to shortening of the propeller blades to facilitate the test. A mechanic who performed work on the engine after the accident reported that the turbocharger was full of oil and that the shaft appeared to be loose. As a result, the turbocharger was replaced with an overhauled unit. The mechanic also reported that the mechanical fuel pump was replaced after the accident but prior to arrival at the engine repair facility. It was reportedly replaced to correct a lean mixture condition, but the mechanic could not verify the reason. Based on the available information, the reason for the engine's partial loss of power could not be determined during the course of the investigation.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (partial) during initial climb defining event
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 2,000 hours in all; 1,018 in this make and model; 1,882 as pilot in command
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 785 hours
- Last inspection: annual inspection, April 12, 2012
- Seats: 6
- Landing gear: retractable
- Engine: Cont Motor TSIO-520 SER (piston); 0 hours total
The flight
- Departed from: ARR Sugar Grove IL at 1:50 pm
- Destination: OSH Oshkosh WI
- Flight plan: none
- Runway 36, 3,198 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 160° at 9 knots
- Visibility: 9 statute miles
- Sky: scat at 25,000 ft
- Temperature: 79°F (26°C), dew point 70°F (21°C)
- Altimeter: 29.87 inHg
- Observation at 1:52 pm from ARR
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.